August 13, 2019

The seizure of Yemen's de facto capital, Aden, by a secessionist group sets conditions for an expansion of Yemen’s civil war that will strengthen al Qaeda in the Arabian Peninsula (AQAP) and the Iranian-backed al Houthi movement. Yemen’s fragmenting since 2015, a trend exacerbated by the manner by which the Saudi-led coalition has engaged with and supported Yemeni factions, undermines US interests. The seizure of Aden widens divisions between Yemeni forces that are nominally aligned against the al Houthi movement. It could also prevent Yemeni counterterrorism forces from sustaining operations against AQAP.

Security forces under the command of the Transitional Political Council for the South (STC) seized control of Aden from the internationally recognized government of President Abdu Rabbu Mansour Hadi on August 10 after four days of fighting. STC Vice President Hani bin Brik called for forces to take control of the capital on August 7 at the funeral of influential southern commander Munir al Yafa’i aka Abu Yamama. STC officials have blamed members of the al Islah party, Yemen’s Islamist party, for facilitating the al Houthi attack on August 1 that killed Abu Yamama and dozens of other STC-aligned soldiers.[1] The ensuing clashes killed at least 70 and spread throughout the city.[2] The Yemeni Minister of Information acknowledged a “successful coup” on August 11 as he left Aden for the Yemeni government-in-exile in Riyadh, Saudi Arabia.[3] Saudi Arabia brokered a ceasefire on August 11 and will host immediate talks between the STC and the Yemeni government in Jeddah.[4]

The STC’s coup was not unexpected. The STC formed, with UAE support, in May 2017, with the ultimate goal of reconstituting an independent state in southern Yemen. President Hadi had dismissed the STC’s president, Aydarus al Zubaidi, from his previous position as governor of Aden in April 2017, prompting the STC’s formation.[5] The STC built out its media capabilities and then turned to expanding its influence across Yemen’s southeast. It established offices in southern governorates later in 2017.[6] STC-led protests in Aden in January 2018 turned violent, and STC supporters took control of much of the city. The UAE and Saudi Arabia intervened and deterred the STC from going farther at the time.[7] The STC has strengthened since then by backfilling governance gaps in southern Yemen, which have persisted despite four years of Saudi-led coalition support to the Yemeni government.[8] The STC has been preparing to assume control of southern Yemen.

A combination of factors contributed to the timing of the STC’s decision to seize Aden. The UAE, which had used the leverage of its military support and presence to keep Yemeni factions in check, reduced its military footprint in Yemen in early summer 2019.[9] The STC correctly assumed that the UAE shift away from the anti-al Houthi fight in Yemen removed the constraints the UAE had placed on the STC and that the UAE would not intervene against it. The STC has also been at loggerheads with the al Islah party, which has gained influence in the Yemeni government as President Hadi has sought to counterbalance southern interests and anti-al Islah UAE influences. The al Islah party seeks to preserve a unified Yemeni state and implement Islamist governance across the country, in contrast to the STC’s desire for a more secular southern Yemeni state. The STC had previously petitioned the UN in March 2019 to address the south’s wish for self-determination as part of the UN-led peace process in Yemen.[10]The temporary alignment of the STC with the Yemeni government is over.

Conditions for the outbreak of renewed conflict between the STC and the government and an intra-southern conflict have been set. The Yemeni government and the STC are unlikely to resolve their differences peacefully. The STC still recognizes the Yemeni government but demands the resignation of President Hadi’s entire government and control of Aden—a demand the Hadi government will not accept.[11] The Hadi government is even weaker, however, having lost its foothold in the south and maintaining only nominal representation in parts of northern and central Yemen.

The STC does not represent all southern Yemenis, however. Influential members of the Southern Movement, al hirak al janubiyya, criticized the STC’s actions in Aden.[12] Divisions among southerners may ripple through Yemen’s south as powerbrokers stake their positions. The anti-STC alignment of Southern Movement members, al Islah members, and others who would seek to prevent the STC’s control of southern Yemen may unify into an armed opposition to the STC.

The destabilization of southern Yemen would reverse gains made by the US and its counterterrorism partners against AQAP, which had been al Qaeda’s most virulent affiliate. AQAP capitalized on Yemen’s descent into civil war in 2015 to expand its haven in southern Yemen. US and UAE counterterrorism operations have degraded AQAP considerably since 2016.[13] The UAE trained and enabled Yemeni forces to combat AQAP. These UAE-backed Yemeni security forces, including the al Hizam Brigades in Aden, Lahij, and Abyan, and the Elites in Shabwah and Hadramawt, also have some allegiances to the STC. Some participated in the recent clashes in Aden and others have declared allegiance to STC President al Zubaidi.[14] AQAP could reestablish its influence in populated areas across southern Yemen should these forces lift the counterterrorism pressure to focus on the fight for control of southern Yemen. Active conflict or a governance vacuum also creates opportunities for AQAP to expand.

Conflict in southern Yemen would splinter the forces fighting the al Houthi movement, giving the al Houthis an opportunity to expand and consolidate their influence in northern and central Yemen. UAE-backed National Resistance Forces under the command of Tariq Saleh, the nephew of late President Ali Abdullah Saleh, or the Southern Giants Brigade, another UAE-backed force, could redeploy from the Red Sea coast to southern Yemen in the event of a protracted conflict in the south.[15] Such a move would leave the al Houthi movement better positioned to attack international shipping around the Bab al Mandab Strait. The al Houthi movement may conduct additional strikes similar to the August 1 strike in Aden in an attempt to instigate further clashes between southern forces and Hadi government-aligned forces.

The STC’s seizure of Aden underscores the shortcomings of the US decision to subcontract the protection of its interests in Yemen to Gulf partners. Emirati support for the STC strengthened and emboldened the group even while the UAE publicly maintained its commitment to Yemeni unity and the Hadi government. The UAE is now attempting to distance itself from the STC’s actions in Aden and has urged calm. Some officials in President Hadi’s cabinet nevertheless blamed the UAE for the coup in Aden, underscoring the deep mistrust between the Yemeni government and the Emiratis.[16] Saudi Arabia lacks influence over the powerbrokers in southern Yemen who could maintain a unified state. Some Saudi policies, such as its support for al Islah as a counterweight to the UAE, have also contributed to the current instability.

The US would have to engage diplomatically quite aggressively and quickly to have any hope of facilitating a negotiated resolution to this conflict. It might have to commit some military resources to the effort to gain leverage. Washington is almost certain to take no such steps, however, and it is by no means clear that it would be successful if it tried. Conflict in southern Yemen is thus likely to expand, fracturing the coalition of forces that had been preventing AQAP from reconstituting and pressing the al Houthis. The US must therefore prepare for a renewed terror threat from one of the most aggressive al Qaeda affiliates, as well as for an expanded threat from Iranian-backed elements on the Red Sea.